This invention relates to metal complexes and to addition polymerization catalysts formed therefrom that have improved catalytic performance. More particularly the present invention relates to an addition polymerization catalyst composition comprising a Group 3,4, or Lanthanide metal complex containing an allyl group bonded via an .eta..sup.3 -.pi. bond to the metal. In addition, the present invention relates to certain of the foregoing complexes possessing a novel bridged structure. Finally, the invention relates to a method of using the foregoing catalyst compositions in an addition polymerization process for polymerizing addition polymerizable monomers.
In U.S. Ser. No. 545,403, filed Jul. 3, 1990, pending (published in equivalent form Mar. 13, 1991 as EP-A-416,815) there are disclosed certain constrained geometry metal complexes and catalysts derived by reacting the metal complex with activating cocatalysts. Supported derivatives of such catalysts were prepared by contacting them with a support such as alumina, silica or MgCl.sub.2. In U.S. Pat. No. 5,064,802 (published Mar. 20, 1991 in equivalent form as EP-A-418,044) there are disclosed certain further catalysts formed by reacting metal complexes with ion forming activating cocatalysts that are salts of Bronsted acids containing a noncoordinating compatible anion. The reference discloses the fact that such complexes are usefully employed as catalysts in addition polymerizations. In U.S. Ser. No. 876,268, filed May 1, 1992, now U.S. Pat. No. 5,721,185 (published in equivalent form Dec. 30, 1992 as EP-A-520,732) an alternative technique for preparing cationic constrained geometry catalysts using borane activators is disclosed.
In U.S. Pat. No. 4,892,851 there are disclosed biscyclopentadienyl Group 4 metal complexes, especially complexes of zirconium or hafnium that are usefully employed with alumoxane activating cocatalysts for use in addition polymerizations, especially the polymerization of aliphatic .alpha.-olefins. In a series of patents, W. Spaeleck has disclosed certain ring substituted stereorigid bisindenyl complexes and their use as olefin polymerization catalysts. The bridging group of such complexes generically includes silicon, germanium or tin containing divalent groups containing hydride, halogen, C.sub.1-10 alkyl, C.sub.1-10 fluoroalkyl, C.sub.6-10 aryl, C.sub.6-10 fluoroaryl, C.sub.1-10 alkoxy, C.sub.2-10 alkenyl, C.sub.7-40 aralkyl, C.sub.8-40 aralkenyl or C.sub.7-40 alkaryl groups or ring forming combinations thereof. Such disclosure may be found in U.S. Pat. No. 5,243,001, U.S. Pat. No. 5,145,819, U.S. Pat. No. 5,304,614, U.S. Pat. No. 5,350,817, among others. For the teachings contained therein, the foregoing United States patents and applications are herein incorporated by reference.
It would be desirable if there were provided an improved catalyst system that readily adaptable to forming improved catalyst systems as well as an improved addition polymerization process utilizing such catalyst systems.